End-to-end anastomosis instrument and method for performing same

ABSTRACT

A surgical instrument for performing an end-to-end anastomosis of first and second luminal structures includes a housing having an actuator attached thereto and a selectively removable loading unit attached to a distal end of the housing which supports any array of surgical fasteners at a distal end thereof. The surgical fasteners are simultaneously deformable upon activation of the actuator such that a distal end of each surgical fastener secures each end of each luminal structure to complete the end-to-end anastomosis wherein the resulting eversion is exterior to the luminal structures.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No. 11/429,505filed May 5, 2006, now U.S. Pat. No. 7,743,958, which is a continuationof U.S. application Ser. No. 10/993,544 filed Nov. 19, 2004, now U.S.Pat. No. 7,059,510, which is a continuation application of No.PCT/US03/18295 filed May 30, 2003, which is a continuation of U.S.application Ser. No. 10/160,460 filed May 31, 2002, now U.S. Pat. No.6,769,594 and the disclosures of each of the above-identifiedapplications are hereby incorporated by reference in their entirety.

BACKGROUND

The present disclosure relates to a surgical instrument and method forperforming anastomosis of tubular body structures, and more particularlyto an instrument for joining tubular tissues, for example, duringgastrointestinal procedures.

Surgical stapling devices for applying an annular array of staples orfasteners to tissue are well known in the art. For example, surgicalstapling devices for applying an annular array of staples, as well asdevices for completing a surgical anastomosis through the provision ofanastomosis rings, are well known in gastric and esophageal surgery, forexample in classic or modified gastric reconstruction typically formedin an end to end, end to side, or side to side manner.

These devices generally include a circular array of fasteners such asstaples, anastomosis rings, and the like, while the anvil memberincludes means for completing the circular anastomosis, typically anarray of bucket members that cinch the staples after the staples areexpelled from the fastener assembly, or may include a locking member forthe anastomosis ring.

In use, the anvil is positioned within the lumen of an organ such as thestomach, esophagus, or intestine and the tissue is pulled about andaround the anvil member and tied off, e.g., by a purse string suture,ring mechanism or the like. The fastener assembly is then positionedwithin the opposite end of the lumen and the tissue is pulled about andaround the fastener assembly over the staple array and also tied off. Atthis point the tissue is positioned between the anvil and the fastenerassembly. The anvil is typically slowly retracted (or advanced) toapproximate the two tissue halves prior to deformation of the staplesusually by virtue of a wing-nut and worm gear assembly which allows asurgeon to methodically advance the anvil towards the staple array tohold the tissue between the anvil and the fastener assembly. Many priorart devices also provide a visual indicator to signal the surgeon whenthe anvil has reached a firing position adjacent the staple or fastenerassembly.

The surgeon then unlocks a safety device deform the staples against theanvil. As the staples or the fasteners are expelled from the fastenerassembly, a circular knife typically follows the application of thestaples to excise unwanted tissue at the anastomosis site. Theinstrument is then removed from the lumen of the organ.

The closing mechanisms associated with the prior art stapling orfastening devices typically utilize a complex worm gear arrangement orscrew bearing member to approximate the spacing between the anvil andthe fastener assembly. As mentioned above, this requires additionalmanipulation of the instrument by the surgeon during the surgery, e.g.,the surgeon must grasp the device with one hand while rotating the knobor wing-like assembly with the other hand. As can be appreciated, movingthe anvil member the full distance towards the fastener assembly can bea time consuming process during the surgical procedure. For example,many of the known prior art devices require 15 to 20 full 360° rotationsof the knob or wing nut assembly to fully close the instrument in orderto fire or expel the staples or fasteners into the tissue.

As can be appreciated, it would be advantageous to eliminate many of theabove steps for performing the circular anastomosis of these tissuestructures to expedite the overall surgical procedure. It would also beextremely advantageous to simplify the overall anastomosis procedure andreduce the level of manual intervention by the surgeon with respect totying off the tubular ends prior to staple deformation. Moreover, itwould be advantageous to provide an instrument which can performend-to-end anastomosis deep within a tubular structure, e.g., colon,where known prior art devices cannot reach and the surgeon is forced toperform an gastrotomy and then make an incision within the side of thetubular structure to utilize these prior art devices.

A need also exists to develop a device which can be useful for lowanterior resection of the colon which has proven difficult with a numberof prior art devices. In addition, it would be useful to provide adevice where the eversion of the tissue is exterior to the colon whichfacilitates future repair if needed and reduces the chances of stenosisat the anastomosis site. It would also be helpful to provide aninstrument which reduces the amount of healthy tissue removed from thesite during the anastomosis.

SUMMARY

The present disclosure relates to a surgical instrument for performingan end-to-end anastomosis of first and second luminal structures, suchas two portions of the small intestine during a gastrointestinalprocedure. The instrument includes a housing having an actuator attachedthereto and a selectively removable loading unit attached to a distalend of the housing. The loading unit is dimensioned to support an arrayof surgical fasteners at a distal end thereof. Upon activation of theactuator, the surgical fasteners simultaneously deform against amoveable anvil such that a distal end of each of the surgical fastenerssecures each end of each luminal structure to complete the end-to-endanastomosis. As can be appreciated, simultaneous deformation of thesurgical fasteners against the movable anvil is advantageous since itgreatly reduces overall operating time compared to manual suturing andalso provides uniformity across the anastomosis site which tends toreduce leakage.

In one embodiment, the surgical fasteners include a convexity and a baseleg which cooperate after deformation of the surgical fasteners tosecurely retain the two luminal structures in close abutment with oneanother. Preferably, the distal ends of the surgical fasteners penetrateat least one of the ends of one of the luminal structures. In anotherembodiment, the surgical fasteners include a base leg and a proximalportion and the surgical fasteners are supported in the loading unit inan angular manner relative to a longitudinal axis extending through theloading unit. Upon deformation, the base legs of the surgical fastenersdeform at an angle relative to the proximal portions of the surgicalfasteners. As can be appreciated, deformation of the surgical fastenersin a radially offset manner allows the surgical fasteners to more fullydeform and essentially “pinch” the two adjoining tissues in closerabutment against one another which tends to further enhance theanastomosis and reduce leakage.

In yet another embodiment according to the present disclosure, theloading unit is disposable and includes two halves which are pivotablerelative to one another. Preferably, the two halves of the loading unitwhen closed form an elongated aperture for receiving the first luminalstructure therethrough. Prior to activation of the actuator, the twohalves of the loading unit are pivotally secured relative to oneanother. Upon actuation, the two halves are unsecured allowing thehalves to pivot relative to one another to release the first luminalstructure from within the elongated aperture. As can be appreciated,automatically releasing the first luminal structure from the loadingunit after deformation is advantageous in the operating theatre since itreduces operating time and manual handling of the luminal structureafter the anastomosis which may unintentionally compromise the overallintegrity of the end-to-end anastomosis.

In still yet another embodiment, the distal end of the loading unitincludes an anvil for retaining the distal ends of the surgicalfasteners and for supporting an everted end of the first luminalstructure. Preferably, the anvil includes an angled surface which causesthe distal ends of the surgical fasteners to deform proximally duringfiring. As mentioned above, this is particularly advantageous because itallows the surgical fasteners to more fully deform and compress or pinchthe tissue into tight abutting relationship with one another to enhancethe anastomosis.

In another embodiment, the loading unit includes a series of elongatedchannels each having a distal end and a proximal end. Each distal end ofeach channel is radially offset from each proximal end such that theproximal and distal ends of the surgical fasteners are supported in aradially offset manner within the loading unit.

The surgical fasteners are deformable upon activation of the actuatorsuch that a distal end of each surgical fastener secures each end ofeach luminal structure to complete the end-to-end anastomosis whereinthe resulting eversion is exterior to the luminal structures. As can beappreciated, making the eversion exterior to the luminal structures isadvantageous since it reduces the chances of fibrin stenosis and/orinfection at the anastomosis site.

In another embodiment of the present disclosure, the handle includes alocking flange which locks the handle in an actuated configuration.Preferably, the locking flange is bifurcated and cooperates with arelease tab to allow the user to selectively release the selectivelydisposable loading unit. The housing advantageously includes a thumb tabwhich is movable from a first position for receiving the selectivelydisposable loading unit to a second position for securing theselectively disposable loading unit. As can be appreciated, thesefeatures are advantageous since they tend to greatly simplify theoverall operation of the surgical instrument and provide the surgeonwith certain lockout controls and safety mechanisms during and after thefiring processes.

In yet another embodiment, the actuator includes at least one cammember. Preferably, the cam member includes two cam followers which ridealong two cam slots defined within the cam member. Advantageously, eachcam follower mechanically engages first and second retracting sleeves,respectively, such that movement of the cam follower moves a respectiveretracting sleeve.

Preferably, one of the cam slots includes two cam stages, a first stagefor retracting a first retracting sleeve for deformation of the surgicalfasteners and a second stage for retracting the first retracting sleeverelative to the second retracting sleeve. Advantageously, movement ofthe first retracting sleeve in the second stage unsecures the halves ofthe selectively disposable loading unit to allow the halves to pivotrelative to one another to release the first luminal structure fromwithin the aperture. As can be appreciated and as mentioned above, thisreduces unnecessary handling of the luminal structures after theanastomosis.

The present invention also relates to a method for creating anend-to-end anastomosis between first and second luminal structures. Themethod includes the steps of: providing a surgical instrument whichincludes: a housing having an actuator; a disposable loading unitremovably mounted to the housing, the disposable loading unit beingconfigured to releasably support a plurality of surgical fasteners; anda retractable anvil being movable to simultaneously deform the surgicalfasteners. The method also includes the steps of: inserting an end ofthe first luminal structure into a passage defined within the loadingunit; everting the first luminal structure over the retractable anvil;inserting a distal end of the disposable loading unit into an end of thesecond luminal structure such that a distal end of each of the pluralityof fasteners and the first luminal structure are sufficiently insertedinto the second luminal structure and the intimae of the two luminalstructures abut one another; and activating the actuator to retract theanvil to simultaneously deform the surgical fasteners and, preferably,to cause distal and/or proximal ends of a plurality of surgicalfasteners to penetrate the luminal structures and complete theend-to-end anastomosis wherein the resulting eversion is exterior to theluminal structures.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects and features of the present invention will become apparentfrom the following detailed description considered in connection withthe accompanied drawings. It should be understood, however, that thedrawings are designed for the purpose of illustration only and not as adefinition of the limits of the invention.

An illustrative embodiment of the subject surgical instrument and methodare described herein with reference to the drawings wherein:

FIG. 1 is a perspective view of a surgical instrument constructed inaccordance with an embodiment of the present disclosure;

FIG. 2 is an enlarged, partial perspective view of a single use loadingunit (hereinafter “SULU”) constructed in accordance with a preferredembodiment of the present disclosure;

FIG. 2A is an enlarged, perspective view of the indicated area of detailof FIG. 2;

FIG. 3 is a perspective view of a surgical fastener which is designedfor operative engagement with the SULU for creating an end-to-endanastomosis between two luminal vessels;

FIG. 4 is a side view the surgical instrument of FIG. 1;

FIG. 4A is a left, side view of a handle/actuator assembly of thesurgical instrument of FIG. 1 shown without a cover plate attachedthereto;

FIG. 5 is an enlarged, perspective view of a distal end of the actuatorassembly shown in a pre-loading position to receivingly engage the SULU;

FIG. 6 is a reverse, perspective view of the SULU of FIG. 2;

FIG. 6A is a reverse, perspective view of a lower half of the SULU ofFIG. 2;

FIG. 7 is a perspective view with parts separated of the SULU of FIG. 2;

FIG. 7A is a greatly enlarged, perspective view of the indicated area ofdetail of FIG. 7;

FIG. 7B is a greatly enlarged, perspective view of the indicated area ofdetail of FIG. 7;

FIG. 7C is an enlarged, perspective view of a base portion of a firstretracting sleeve;

FIG. 7D is a greatly enlarged, perspective view of the indicated area ofdetail of FIG. 7C;

FIG. 8 is a greatly enlarged, perspective view of the indicated area ofdetail of FIG. 7;

FIG. 9 is a greatly enlarged, perspective view of the indicated area ofdetail of FIG. 7;

FIG. 10 is a perspective view of the actuator assembly with the coverplate shown separated;

FIG. 11 is a perspective view the actuator assembly of FIG. 10 shownwith parts separated;

FIG. 12 is a horizontal cross-sectional view of the surgical instrumentof FIG. 1 shown preloaded for firing;

FIG. 13 is a horizontal cross-sectional view of the indicated area ofdetail of FIG. 12;

FIG. 13A is a greatly enlarged horizontal cross sectional view of thearea indicated in detail of FIG. 13;

FIG. 14 is a top cross-sectional view of the surgical instrument takenalong section line 14-14 of FIG. 12;

FIG. 15 is a greatly enlarged top cross-sectional view of the areaindicated in detail of FIG. 14;

FIG. 16 is a front cross-sectional view of the surgical instrument takenalong section line 16-16 of FIG. 12;

FIG. 17 is a perspective view of the SULU with a first luminal structureinserted therethrough;

FIG. 18 is perspective of the SULU with an end of the first luminalstructure everted over a distal end of the disposable unit beinginserted into a second luminal structure;

FIG. 19A is enlarged, cross-sectional view of the second luminalstructure;

FIG. 19B is enlarged, cross-sectional view of the first luminalstructure shown everted atop the distal end of the SULU;

FIG. 20 is a side cross-sectional view showing the first and secondluminal structures in position atop the distal end of the SULU prior toactivation of the actuator;

FIG. 21 is a side view of the actuator assembly without the cover plateduring a first firing stage of the instrument and showing the internalmovement of a first retractor within the actuator assembly;

FIG. 21A is a side cross-sectional view showing the relevant positionsof the internal working components of the actuator assembly after thefirst firing stage;

FIG. 21B is a side cross-sectional view showing the movement of the SULUduring the first firing stage to deform the surgical fasteners;

FIG. 21C is a greatly enlarged side cross-sectional view of the areaindicated in detail in FIG. 21B;

FIG. 21D is a greatly enlarged perspective view of the surgical fastenershown in a “stapled” configuration;

FIG. 21E is a side view showing the relevant movement of a lockingsleeve after the first firing stage;

FIG. 22 is a side cross-sectional view of the actuator assembly duringthe second firing stage and showing the internal movement of a secondretractor within the actuator assembly;

FIG. 22A is a side cross-sectional view of the SULU during the secondfiring stage and showing the movement of a second retracting sleevewhich moves as a direct result of the movement of the second retractorto release the surgical fasteners;

FIG. 22B is a greatly enlarged side cross-sectional view showing theretracting movement of a finger-like retention prong which moves as adirect result of the movement of the second retractor;

FIG. 23 is a perspective view of the SULU showing the pivotable movementof the two supports which open after firing to release the first luminalstructure;

FIG. 24A is a view showing a completed end-to-end anastomosis;

FIG. 24B is an enlarged, schematic view of a completed end-to-endanastomosis utilizing a prior art device showing an eversion on theinterior of the luminal structures;

FIG. 24C is an enlarged, schematic view of a completed end-to-endanastomosis utilizing the presently disclosed surgical instrumentshowing an eversion on the exterior of the luminal structures;

FIG. 24D is side view of a completed end-to-end anastomosis utilizingthe presently disclosed surgical instrument;

FIG. 25A is a view showing the surgical fastener staple pattern of theinstrument described with respect to FIGS. 1-24C;

FIG. 25B. is a view showing one possible alternative surgical fastenerstaple pattern;

FIG. 26 is an enlarged cross-section showing the ends of the two luminalstructures after anastomosis and engaged between the surgical fastener.

DETAILED DESCRIPTION

Various embodiments of the surgical instrument and method disclosedherein will be described in terms of a gastrointestinal procedurewherein an end-to-end circular anastomosis is created by joining twosections of a two luminal structures, e.g., the colon and/or the smallintestine. Alternatively, the presently disclosed surgical instrumentmay also be utilized in performing end-to-end anastomosis of othertubular luminal body structures for other surgical procedures.

In the drawings and in the description which follows, the term“proximal”, as is traditional, will refer to the end of the apparatuswhich is closer to the user, while the term “distal” will refer to theend which is further from the user.

Referring now in detail to the drawing figures in which like referencenumerals identify similar or identical elements, one embodiment of thepresent disclosure is illustrated generally in FIG. 1 and is designatedtherein as surgical instrument 10. Surgical instrument 10 includes twoprincipal components, namely, an actuator assembly 20 and a disposableloading unit (“DLU”) or a single use loading unit (“SULU”) 100, whichalong with their internal working components, mechanically cooperate todeform a surgical fastener 260 to complete an anastomosis betweenluminal structures.

The particular surgical instrument 10 shown in the various figures ispreferably designed to deform an array of surgical fasteners similar tofastener 260 shown in FIG. 3 which is generally L-shaped and includes abase leg 264 and an upwardly extending support leg 262. Preferably, baseleg 264 includes a distal end 269 which is sufficiently shaped topenetrate a first luminal structure 320 upon deformation of the surgicalfastener 260. The upwardly extending support leg 262 is attached to baseleg 264 at a pivot point 265 and includes an inwardly extending prong267 disposed at its free end designed to surgical fastener 260 inposition after the completed anastomosis. It is envisioned that pivotpoint 265 may also be dimensioned to include a relief or coined section(not shown) which facilitates formation of the surgical fastener 260.

Turning back in detail to FIG. 3, a convexity 263 projects inwardlybetween the base leg 264 and the support leg 262 and is preferablysufficiently dimensioned to cooperate with the base leg 264 to retainthe first luminal structure 320 against the second luminal structure 310in fluid communication after anastomosis as will be explained in greaterdetail below with respect to FIGS. 21B, 24A and 24D. It is envisionedthat the surgical fastener 260 can be arranged on the SULU in differentpatterns/arrays depending upon a particular purpose or to achieve aparticular result.

As best seen in FIGS. 1, 4, 10 and 11, actuator assembly 20 includes aproximal end 24, a distal end 22 and a housing 26 defined therebetweenfor storing the internal working components of the actuator assembly 20.Preferably, a plate 90 covers the internal components of the actuatorassembly 20 when assembled. More particularly, housing 26 includes atleast one mechanical interface 23 a which reciprocates with acorresponding mechanical interface 23 b (FIG. 10) disposed on coverplate 90 to matingly engage the two components 26 and 90.

Actuator assembly 20 also includes a handle 12 which initiates firing ofthe surgical instrument 10 and a spring-loaded thumb tab 30 for loadingthe SULU 100 onto the actuator assembly 20 both of which will beexplained in greater detail below. Preferably, handle 12 is providedwith an ergonomic surface which is contoured and configured to becomfortably gripped by the hand of the user during operation of theinstrument.

Turning briefly to FIG. 11 which illustrates in detail the internalworking components of the actuating assembly 20 which are preferablyassembled and stored within housing 26. More particularly, the actuatingassembly 20 includes a torsion spring 70 which mounts about post 21which protrudes from housing 26. Spring 70 includes a lower arm 74 whichis biased against a lower portion of the housing and an upper arm 72which is biased against a rotating two-stage cam 60.

Handle 12 includes a bushing 19 which protrudes laterally from theproximal end of the handle 12 and pivotally engages a correspondingrecess 29 disposed within the proximal end 24 of housing 26 to allowpivotal movement of the handle 12 with respect to housing 26. Handle 12also includes a vertically extending slot 27 disposed at its proximalend 24 which receives the proximal end of a lever 16 which moves inconjunction with the handle 12. A pair of flanges 14 a and 14 bdownwardly extend from the handle 12 and receive lever 16 therebetween.A mechanical interface 11 a disposed on handle 12 engages acorresponding mechanical interface 11 b disposed on lever 16 to securethe lever 16 to the handle 12. Preferably, lever 16 has a first recess17 shaped to engage and control the movement of the cam 60 duringdownward movement of the handle 12, the purpose of which will beexplained in more detail with respect to FIG. 21A. Lever 16 alsoincludes a second recess 15 which helps to limit lateral movement of thetorsion spring 70 within housing 26.

As mentioned above, actuating assembly 20 also includes a spring-loadedthumb tab 30 which rests atop housing 26 within a longitudinallyextending slot 28 disposed near the distal end 22 thereof. As best seenin FIG. 10, slot 28 is formed by notches 18 a and 18 b of the housing 26and cover plate 90, respectively. Tab 30 includes a thumb guide 35 whichcooperates with a sliding sleeve 32 to facilitate proximal movement ofthe tab 30 for loading the SULU. A downwardly depending flange 34disposed on tab 30 engages a corresponding slot 33 located in a mount 31disposed atop the sliding sleeve 32. Preferably, sliding sleeve 32includes a post 36 which is dimensioned to receive a tension spring 38thereon. Spring 38 is biased between a block 47 disposed within housing26 and a proximal edge 37 of sliding sleeve 32 such that spring 38biases sliding sleeve 32 to a distal-most position proximate distal end22. Preferably, a distal end 39 of sleeve 32 is arcuate or semi-circularand is dimensioned to slidingly engage a corresponding end 82 of a firstretractor 80 to lock the SULU 100 within the actuator assembly 20 afterthe SULU 100 is loaded as will be discussed in more detail below.

Actuator assembly 20 also includes first retractor 80 and a secondretractor 50 which each move by way of movement of the handle 12 which,in turn, imparts movement to the two-stage cam 60. First retractor 80includes distal and proximal ends 82 and 84, respectively, and isgenerally tubular in dimension with the exception of an elongated furrow83 extending proximally from distal end 82 for slidingly supportingsleeve 32. Retractor 80 also includes a slot 85 for receiving a pin 54for affixing the retractor 80 to the cam 60 and another pair of slots 87and 89 located near the proximal end 84 for receiving two cam followers51 a and 51 b, respectively. Preferably, the proximal end 84 isbifurcated to facilitate insertion of the second retractor 50 therein.

As best seen in FIGS. 11 and 16, a guide 81 engages an elongated rib 25a in housing 26 and an elongated rib 25 b in cover plate 90 to slidinglymount the retractor 80 to housing 26. Guide 81 is dimensioned slightlylonger than rib 25 a to permit proximal movement of the first retractor80 relative to the housing 26 upon activation of the handle 12.Preferably, a protective tube 95 is telescopically disposed about thefirst retractor 80 and moves in conjunction with the sliding sleeve 32by way of slot 96 which secures mount 31 of the sliding sleeve 32therein. It is anticipated that protective tube 95 also helps torestrict lateral movement of the first retractor 80 during retraction.Tube 95 also includes an elongated channel 97 which generally alignswith guide 81 located in the first retractor 80 to mount both componentsto ribs 25 a and 25 b.

It is contemplated that proximal movement of tab 30 will impartreciprocating proximal movement to the sliding sleeve 32 to exposecarriages 86 and 88 disposed within the first retractor 80 which aredesigned to receive a pair of first and second retracting sleeves 110and 120 (FIGS. 7-9) of the SULU 100. More particularly, and as best seenin FIG. 5, carriage 86 is generally circular in shape and is designed toreceive an outer lip 122 formed by the union of end 122 a and 122 b ofsecond retracting sleeve 120 of the SULU 100. Preferably, carriage 86 isdimensioned larger that the lip 122 so as to permit proximal movement ofthe second retracting sleeve 120 relative to the first retracting sleeve110 as will be explained in more detail with respect to FIG. 22A.Carriage 88 is likewise circular in shape and receives outer lip 112 ofthe first retracting sleeve 110.

Actuator assembly 20 also includes a handle lock 40 which rests atop thefirst retractor 80 and extends laterally between the housing 26 and thecover plate 90. More particularly, handle lock 40 is mounted withinslots 93 a and 93 b as best seen in FIG. 10. Handle lock 40 includes apost 43 which receives a spring 45 for biasing handle lock 40 against aledge 49 of the housing 26 (FIG. 12). Handle lock 40 also includes apair of flanges 42 a and 42 b which align with flanges 14 a and 14 bdisposed on handle 12. As shown best in FIGS. 21 and 22, downwardmovement of the handle 12 forces the handle lock 40 initially distallyagainst spring 45 until flanges 14 a and 14 b clear flanges 42 a and 42b at which point spring 45 forces handle lock 40 proximally to lockflanges 42 a and 42 b atop flanges 14 a and 14 b and to lock handle 12in a downwardly disposed position. Preferably, flanges 42 a and 42 bdefine a slot 41 for receiving lever 16 therebetween.

Actuator assembly 20 also includes a second retractor 50 which includesan elongated arm 52 having a key-like distal end 53 and a T-shaped heelsection 56. Preferably, T-shaped heel section 56 attaches to a tensionspring 55 disposed proximally thereof. Second retractor 50 is preferablybifurcated at its proximal end forming two longitudinally extending fins58 a and 58 b each having a slot 57 and aperture 59 for receiving camfollowers 51 and 51 b, respectively. It is contemplated that spring 55is biased against an elongated stop 65 which rests atop arm 52 andbiases heel section 56 proximally when the second retractor 50 isretracted which will be explained in more detail below with respect tothe operation of the surgical instrument 10.

As mentioned above, the first retractor 80 is affixed to two-stage cam60 by pin 54. More particularly, cam 60 includes an aperture 61 locatednear the distal end thereof for receiving pin 54 which affixes the cam60 to the first retractor 80. Cam 60 also includes a pair of generallyvertical arcuately-shaped slots 62 and 64 which each include twodiscrete stages, namely 62 a, 62 b and 64 a, 64 b, respectively, forimparting movement to corresponding followers 51 a and 51 b. A nub 66 islocated near the uppermost portion of the cam 60 and is dimensioned toslideably engage recess 17 located in lever 16 as best illustrated inFIG. 12.

It is contemplated that during downward movement of handle 12, lever 16will bias nub 66 downwardly such that nub 66 rides proximally alongrecess 17 and causes cam 60 to pivot downwardly about pin 54 as shownbest in FIGS. 21A and 22. In turn, followers 51 a and 51 b will ridealong slots 64 and 62 and cause the first and second retractors 80 and50 to move in a proximal direction which will be explained in moredetail below. Preferably, recess 17, nub 66 and slots 64 and 62 can bedimensioned to control the movement and timing of the cam followers 51 aand 51 b. For example, it is envisioned that the stages 64 a, 64 b and62 a and 62 b can be dimensioned to control the timing and movement ofthe first and second retractors which, in turn, can effect theefficiency of the anastomosis.

Elongated stop 65 is preferably affixed to the distal end of cam 60 andrests atop the second retractor 50. Elongated stop 65 includes a distalend 69 and a proximal end 67 which includes two extending portions 67 aand 67 b each having an aperture 63 a and 63 b, respectively, disposedtherethrough. Preferably, end 69 of stop 65 is sufficiently dimensionedsuch that it engages a corresponding biasing post 102 located within theSULU 100.

Preferably, the second retractor 50, the cam 60 and the elongated stop65 are pre-assembled prior to insertion into the first retractor 80.More particularly and as best illustrated in FIGS. 10-12, elongated stop65 is positioned atop arm 52 of the second retractor 50 between T-shapedheel section 56 and end 53. Apertures 63 a and 63 b of stop 65 alignwith aperture 61 of cam 60 such that once the cam 60 and the elongatedstop 65 are inserted within slot 91 of the first retractor 80, pin 54locks the two components 65 and 60 together through slot 85.

Cam 60 is positioned between the extending fins 58 a and 58 b of thesecond retractor 50 such that, when the retractor 50 and cam 60 areinserted within slot 91 of the first retractor, followers 51 a and 51 bare inserted through slot 87 and slot 89, respectively, and slideablycouple the two components 50 and 60 within the first retractor 80.Handle lock 40 is then positioned atop the first retractor 80 asdescribed above. First retractor 80 is then mounted on ribs 25 a and 25b of housing 26 and cover plate 90, respectively, and tab 30 along withsliding sleeve 32 are engaged thereon. Handle 12 and lever 16 are thenassembled as described above and pivotably mounted about post 21. Spring70 is then positioned accordingly so as to bias handle 12 againsthousing 26.

Turning now to FIGS. 7-9 which show an exploded view of the internalworking components of the SULU 100 which as mentioned above includesfirst retracting sleeve 110 and second retracting sleeve 120 whichcooperate to deform fasteners 260 and securely fasten the two luminalstructures 320, 310 in fluid communication as shown in FIGS. 24A and24D.

More particularly and as best seen in FIGS. 7-7D, first retractingsleeve 110 includes a tube-like base 110 a and an arcuate sleeve cap 110b which together define the first retracting sleeve 110. Base 110 aincludes a circular lip 112 located at its proximal end and asemi-circular anvil 118 a located at the opposite end. A locking tab 116a having an elongated slit 182 a located therein is disposed between lip112 and anvil 118 a. A longitudinally-extending slot 114 a is disposedbetween the lip 112 and the locking tab 116 a. At least one interface117 a downwardly depends from base 110 a to mechanically engage acorresponding mechanical interface 117 b disposed on sleeve cap 110 b(FIG. 7). A flange 113 a is preferably disposed beneath slot 114 a andis sufficiently dimensioned to engage corresponding flanges 113 b ₁ and113 b ₂ located on sleeve cap 110 b. Slot 114 a is sufficientlydimensioned to receive a tab 138 a (FIG. 13) which projects from anupper surgical fastener support 130 a which is explained in more detailbelow.

Sleeve cap 110 b includes a semi-circular anvil 118 b and a bifurcatedproximal end 113 composed of flanges 113 b ₁ and 113 b ₂ which togetherdefine a slot 114 b for receiving a tab 138 b which projects from alower surgical fastener support 130 b which is explained in more detailbelow. Sleeve cap 110 b also includes mechanical interfaces 117 b whichcouples with corresponding mechanical interfaces 117 a disposed on base110 a to engage sleeve cap 110 b with base 110 a. A locking tab 116 bhaving an elongated slit 182 b located therein is disposed betweenproximal end 113 and anvil 118 b. A longitudinally-extending opening 111b is preferably disposed proximate locking tab 116 b and aligns with acorresponding opening 111 a in base 110 a (FIG. 7C) such that the firstluminal structure 320 can be received therethrough as seen best in FIGS.17 and 18.

FIGS. 2A and 7D show a greatly enlarged view of anvil 118 a whichincludes a semi-annular array of fastener support channels or cradles119 a each configured and dimensioned to support a surgical fastener 260therein. Sleeve cap 110 b also includes fastener support channels 119 bwhich, when base 110 a and sleeve cap 110 b are assembled, align to forma circular array about the internal surfaces of anvil 118 a and 118 b.It is envisioned that anvils 118 a and 118 b can be designed to supportdifferent arrays of surgical fasteners 260 depending upon a particularpurpose. Each channel 119 a and 119 b is preferably separated by ananchor 187 a and 187 b (FIG. 7) which releasably retains a projectingfinger 124 a, 124 b of second retracting sleeve 120 (FIG. 2A).

Support channels 119 a and 119 b each include proximal ends 186 a and186 b and distal ends 184 a and 184 b which are radially offset from oneanother to seat surgical fastener 260 within channels 119 a and 119 b ina radially offset manner the purpose of which will be explained belowwith respect to the operation of the surgical instrument 10. The distalend 184 a of each channel 119 a is preferably arched so as to correspondto the arcuate shape of the end of the surgical fastener 260 as bestseen in FIG. 13A. It is anticipated that arching the distal end 184 awill cause the surgical fastener 260 to deform upwardly and proximallyupon retraction of the first retracting sleeve 110 by the firstretractor 80 as explained below with reference to FIGS. 21-22.

FIGS. 7-7D also show second retracting sleeve 120 which includes anupper cuff 120 a, a lower cuff 120 b and an outer cap 128 which togetherdefine the second retracting sleeve 120. More particularly, upper cuff120 a includes a semi-annular lip 122 a at one end and a plurality ofretention fingers 124 a at the opposite end. Upper cuff 120 a alsoincludes a first slot 101 which preferably aligns with slot 114 a of thefirst retracting sleeve 110 a to receive tab 138 a of upper fastenersupport 130 b therethrough. A second slot 126 a receives locking tab 116a when cuff 120 a is slideably mounted atop base 110 a. Interfaces 129 amechanically engage corresponding interfaces 129 b located on lower cuff120 b.

Lower cuff 120 b includes a bifurcated proximal end 107 which comprisesflanges 107 b ₁ and 107 b ₂ which define a slot 108 for receiving tab138 b of lower fastener support 130 b therethrough and a plurality ofretention fingers 124 b which extend from the opposite end thereof. Aslot 126 b is disposed between the flanges 107 b ₁, 107 b ₂ and thefingers 124 b for receiving locking tab 116 b of the sleeve cap 110 bwhen cuff 120 b is slideably mounted thereon. A longitudinally-extendingopening 121 b is disposed proximate slot 126 b and aligns with acorresponding opening 121 a in upper cuff 120 a and also aligns withopenings 111 a and 111 b of the first retracting sleeve 110 such thatthe first luminal structure 320 can be received therethrough as seenbest in FIGS. 17 and 18.

A semi-circular cuff cap 128 is disposed atop lower cuff 120 b andmechanically interfaces with upper cuff 120 a such that semi-circularlips 122 a and 122 b form circular lip 122. More particularly, cuff cap128 includes a plurality of detents 123 b which mechanically engage acorresponding plurality of notches 123 a located in upper cuff 120 asuch that the cuff cap 128, upper cuff 120 a and lower cuff 120 b allmove in unison upon retraction of the second retracting sleeve 120.Sleeve cap 128 is preferably bifurcated at its distal end forming slot109 which is dimensioned to receive tab 138 b.

As can be appreciated, fingers 124 a and 124 b move upon retraction ofthe second retracting sleeve 120 to release the surgical fasteners 260after firing. More particularly and as best seen in FIGS. 2A and 7A, thedistal end of each finger 124 a is forked and includes a first prong 127a which retains a surgical fastener 260 within the fastener supportchannels 119 a and a second prong 125 a which interlocks with anchor 187a to releasably lock the finger 124 a to the first retracting sleeve 110until released by the second retractor 50 (FIGS. 22A and 22B) which willbe explained in more detail with respect to the operation of thesurgical instrument 10. Likewise, each finger 124 b of lower cuff 120 bincludes prongs 127 b and 125 b which operates in the same manner.

As mentioned previously, the SULU 100 also includes fastener support 130which has an upper support 130 a and a lower support 130 b which, whenassembled, internally house the first and second retracting sleeves 110and 120, respectively, along with their individual working components.Upper support 130 a and lower support 130 b each include a distal end135 a and 135 b each having an array of braces 137 a and 137 b,respectively, which project radially from distal ends 135 a and 135 b.As best illustrated in FIG. 2, each brace 137 a and 137 b supports anupwardly extending support leg 262 of a surgical fastener 260 disposedwithin one of the channels 119 a or 119 b. A plurality of radiallyextending slots 139 a and 139 b are disposed between each support brace137 a, 137 b for retaining a surgical fastener 260 therein and forrestricting unwanted lateral movement of each fastener 260. It isanticipated that each surgical fastener 260 is positioned within a slot139 a, 139 b such that convexity 263 projects outwardly from brace 137a, 137 b and, after anastomosis, cooperates with the base leg 264 toretain the two luminal structures 32- and 310 in close abutment againstone another (FIGS. 21B, 24A and 24D).

Upper support and lower support 130 a and 130 b, respectively, alsoinclude hinges 136 a and 136 b which, when the SULU 100 is assembled,matingly engage one another to allow pivotable movement between thesupports 130 a and 130 b from an open position (FIG. 23) to a closedposition (FIG. 2). Preferably, a pin 180 secures the two hinges 136 aand 136 b together (FIG. 6). Upper and lower supports 130 a and 130 beach include a longitudinally-extending opening 133 a (FIG. 23) and 133b which aligns with openings 121 a, 121 b, 111 a and 111 b describedabove to receive the first luminal structure 320 therethrough as seenbest in FIGS. 17 and 18. Longitudinally oriented slots 131 a and 131 bare disposed adjacent openings 133 a and 133 b on the upper and lowersupport members 130 a and 130 b, respectively, for receiving lockingtabs 116 a and 116 b in much the same manner as described above withrespect to slots 126 a and 126 b of the second retracting sleeve 120.

Lower support 130 b includes a pair of shoulders 132 a and 132 bdisposed on opposite sides of opening 133 b for slideably receiving acorresponding pair of flanges 144 a and 144 b associated with an upperlocking sleeve 140 a. More particularly, each flange 144 a and 144 bextends distally from the upper locking sleeve 140 a to define a notch149 a and 149 b, respectively, therein for receiving shoulders 132 a and132 b of lower support 130 b.

Upper locking sleeve 140 a includes a C-shaped clip 146 a (FIG. 8)disposed therein which has pair of opposing hooks 147 a forsnap-lockingly engaging slit 182 a of locking tab 116 a of firstretracting sleeve 110. A lower locking sleeve 140 b operates in asimilar manner and includes a pair of opposing hooks 147 b forsnap-lockingly engaging slit 182 b of locking tab 116 b of firstretracting sleeve 110. Upper locking sleeve 140 a also includes anopening 141 a which aligns with openings 133 a, 133 b, 121 a, 121 b, 111a and 111 b described above to receive the first luminal structure 320therethrough as seen best in FIGS. 17 and 18. It is envisioned that uponretraction of the second retracting sleeve 120, upper locking sleeve 140a will move proximally relative to shoulders 132 b and 134 b anddisengage shoulders 132 a, 132 b which, in turn, will allow the upperand lower supports 130 a and 130 b to pivot about pin 180 and releasethe first luminal structure 320 (FIGS. 21E and 23). This will beexplained in greater detail with respect to the operation of theinstrument as described below.

SULU 100 also includes a biasing post 102 which mechanically alignsupper and lower supports 130 a and 130 b in fixed relation relative toone another. More particularly, biasing post 102 includes a proximal end103 and a distal end 105 and has a vertically oriented cavity 106disposed therethrough for receiving tabs 138 a and 138 b of the upperand lower supports 130 a and 130 b, respectively. As mentioned above,tabs 138 a and 138 b pass through slots 114 a, 114 b of the firstretracting sleeve 110 and through slots 101, 108 and 109 of the secondretracting sleeve 120 and mechanically align with one another withincavity 106 as best seen in FIG. 21B.

Turning now in detail to the loading of the SULU 100 within actuatorassembly 20 as best seen in FIG. 5, thumb tab 30 is moved proximally byway of thumb guide 35 against spring 38 which, in turn, moves sleeve 32and protective cover 95 proximally to expose carriages 86 and 88. TheSULU 100 is then loaded within actuator assembly 20 by placing lip 112within carriage 88 and lip 122 within carriage 86. As best shown in FIG.13, lip 122 is positioned near the distal end of carriage 86 whichallows lip 122 and, hence, second retracting sleeve 120, to moveindependently from the first retracting sleeve upon activation of thesecond retractor 50. In contrast, carriage 88 is dimensioned smallerthan carriage 86 such that lip 112 fits snugly within carriage 88. Oncethe SULU is positioned within carriages 86 and 88, thumb tab 30 isreleased and spring 38 biases sleeve 32 and protective cover 95 distallyover lips 112 and 122 to lock the SULU 100 within the actuator assembly20.

In use and as shown in FIGS. 17-24D, the user inserts a free end 322 ofthe first luminal structure, e.g., intestine, into opening 133 of theSULU and pulls via a surgical hook or graspers the free end 322 towardsthe distal end of the SULU 100. The user then everts the first luminalstructure 320 over the anvils 118 a, 118 b of the SULU 100 such that thefree end 322 is retained by end 269 of the surgical fasteners 260 (seeFIG. 19B). Everting of the first luminal structure 320 may be achievedby any suitable known instruments and/or techniques such as by usinggraspers. The first luminal structure 320 is preferably everted over thefull length of the base leg 264 such that the first luminal structure320 resides in close proximity to convexity 263 as best seen in FIG.19B.

The first luminal structure 320 is then secured to the distal end of theSULU 100 by a suture or other convention means or by virtue of anadditional securing mechanism (not shown) disposed on the SULU 100. Theuser then inserts the end of the SULU 100 and the first luminalstructure 320 into the second luminal structure 310 such that the distalend 269 of each of the plurality of fasteners 260 and the everted endportions 322 of the first luminal structure 320 are sufficientlyinserted into end 312 (FIGS. 18 and 20A). As seen best in the enlargedview of FIG. 20, the support leg 262, convexity 263 and prong 267 ofeach surgical fastener 260 remains outside incision 312. The instrumentis now preset for firing.

FIGS. 21-22 show the firing sequence of instrument 10, i.e., when thehandle 12 is depressed by the user. As best shown in FIGS. 21 and 21A,as handle 12 is depressed downwardly in the direction of reference arrow“A”, lever 16 simultaneously imparts movement to both handle lock 40 andcam 60. More particularly, downward movement of handle 12 causes flanges14 a and 14 b of lever 16 to urge flanges 42 a and 42 b of handle lock40 distally against spring 45 in the direction of reference arrow “B”(FIG. 21). At the same time, handle 12 causes recess 17 of lever 16 tobias nub 66 which, in turn, causes cam 60 to deflect downwardly andproximally as best seen in FIG. 21A. Preferably, recess 17 in lever 16is dimensioned to control the specific movement of nub 66 within recess17 which, in turn, controls the overall movement of cam 60. Downward andproximal movement of cam 60 causes cam followers 51 a and 51 b to movewithin the first cam stages 64 a and 62 a of slots 64 and 62,respectively, which, in turn, moves the first retractor 80 andprotective cover 95 proximally in the direction of reference arrow B′.

As seen best in FIG. 21, as retractor 80 moves proximally as a result ofthe movement of cam followers 51 a and 51 b within slots 64 and 62, slot85 moves proximally until it abuts pin 54. Preferably, when slot 85abuts pin 54, cam 60 is forced more downwardly about pin 54 such thatcam followers 51 a and 51 b move more proximally to engage the secondstages 64 b and 62 b of the cam slots 64 and 62, respectively.

As mentioned above, the first retractor 80 retracts the first retractingsleeve 110 (FIG. 21) which, in turn, causes surgical fasteners 260 todeform as shown in FIGS. 21B and 21D. More particularly and as bestshown in FIG. 21B, proximal movement of the first retractor 80 causesboth the first retracting sleeve 110 and the second retracting sleeve120 to move proximally relative to biasing post 102 until biasing post102 abuts the end 69 of elongated stop 65. As a result, anvils 118 a and118 b deform the distal ends 269 of surgical fasteners 260 upwardly andproximally towards braces 137 a and 137 b, respectively, i.e., arc-likedistal ends 184 a and 184 b cause surgical fasteners 260 to deformupwardly and proximally upon retraction of the first retracting sleeve110. At the same time, the second luminal structure 310 is forcedslightly proximally and extending prongs 267 penetrate to hold thesecond luminal structure 310 in position as best seen in FIG. 22A. FIG.26 illustrates the resulting deformation of clip 260 through the twoluminal structures 320 and 310.

It is anticipated that the radially offset orientation of the oppositeends 186 a, 186 b and 184 a, 184 b of the support channels 119 a and 119b, respectively will cause the opposite ends 267 and 269 of the surgicalfasteners 260 to deform at an angle α relative to one another as bestshown in FIG. 21D. This allows end 269 to deform proximal to braces 137a and 137 b. Preferably, braces 137 a and 137 b have a tapered crosssection to deform end 269 of surgical fastener 260 radially from end 267during deformation.

It is anticipated that the presently disclosed surgical fasteners 260can also include an end 269 which is blunt and which does not penetratethe luminal structures 320 or 310 upon deformation. As can beappreciated, this offers the user the option of performing a lesstraumatic anastomosis.

FIG. 21C shows the resulting position of the spacer 104 of the biasingpost 102 after the first retractor 80 retracts the first and secondretracting sleeves 110 and 120, respectively. More particularly, spacer104 frictionally locks the first retracting sleeve 110 relative to thesecond retracting sleeve 120 and prevents the first retracting sleeve110 from recoiling after firing.

FIG. 21E shows the proximal movement of the locking sleeve 140 a as aresult of the movement of the first retracting sleeve 110. Moreparticularly, when the first retracting sleeve 110 is retractedproximally, locking tab 116 a retracts within slot 131 a of support 130a and biases locking sleeve 140 a in a proximal direction as well asseen by reference arrow “C”. Proximal movement of the locking sleeve 140a relative to support 130 a disengages flanges 142 a and 144 a fromshoulders 132 b and 134 b, respectively, of support 130 b which, inturn, unlocks supports 130 a and 130 b from one another thus permittingpivotal movement of the support members 130 a, 130 b as best seen inFIGS. 21E and 23.

Continued downward movement of handle 12 results in both proximalmovement of the second retractor 50 and engagement of the handle lock 40with the handle 12. More particularly and as best illustrated in FIG.22, as the user continues to move the handle 12 in a downward direction,flanges 14 a and 14 b clear corresponding flanges 42 a and 42 b andspring 45 biases handle lock 40 proximally in the direction of referencearrow “D” to lock the handle 12 in position. Simultaneously, cam 60 isrotated about pin 54 to a point where the second stages 64 a and 62 a ofthe cam slots 64 and 62 effect the movement of the cam followers 51 aand 51 b. More particularly, as cam 60 is forced downwardly, the secondstage 62 a of cam slot 62 moves cam follower 51 b proximally which, inturn, moves the second retractor 50 proximally. The second stage 64 a ofcam slot 64 is generally vertically oriented and, as a result, camfollower 51 a moves vertically upon continued downward movement ofhandle 12. Slot 57 of retractor 50 allows the second retractor 50 toslide proximally relative to cam follower 51 a.

As mentioned above, second retractor 50 moves the key-like end 53 of thesecond retracting sleeve 120 within carriage 86 relative to the firstretracting sleeve 110 as illustrated by reference arrow “E” of FIG. 22A.Proximal movement of the second retracting sleeve 120 retracts theprongs 127 a and 127 b of fingers 124 a, 124 b, respectively, whichreleases the surgical fasteners 260 as illustrated by reference arrow“E” of FIG. 22B.

It is envisioned that the surgical instrument 10 and/or the SULU 100 mayneed to be manipulated to assure consistent and tactful release of thesurgical fasteners 260 from the SULU. For example, it is contemplatedthat after and/or simultaneously with activation of the handle 12, thepresently disclosed methods described herein may include the step ofmanipulating the surgical instrument 10 or SULU 100 relative to thesurgical fasteners 260 to facilitate release thereof, e.g., rotationalor off-axis manipulation relative to axis “A” (See FIG. 5), verticalmanipulation, horizontal manipulation, pivotal manipulation and/or anysimultaneous or sequential combination of these aforedescribedmanipulative movements.

Further, it is contemplated that the surgical instrument 10 or the SULU100 may be manufactured to include an additional activator, lever,handle, pivot element, linkage or the like (not shown) which uponactivation thereof will manipulate the surgical instrument 10 and/orSULU 100 relative to the surgical fasteners 260 in one of the mannersdescribed above to facilitate consistent and tactful release of thesurgical fasteners 260.

As mentioned above, after sleeve 110 is retracted, locking sleeve 140 amoves proximally to allow the two supports 130 a and 130 b to pivot awayfrom one another as shown in FIG. 23 to permit the removal of theintestine 320 from within the SULU thereby completing the end-to-endanastomosis as shown in FIGS. 24A and 24D. FIG. 26 illustrates a sideview of the resulting deformation of surgical fastener 260 through thetwo liminal structures 320 and 310. As can be appreciated, thedeformation of the surgical fastener 260 forms a series of folds 510 inthe tissue 310 which help maintain the anastomosis.

FIG. 25A shows a schematic diagram of the surgical fastener staplepattern which is formed upon actuation of the instrument described abovewith respect to FIGS. 1-25B. More particularly, the surgical fastenersare supported by the fastener support braces 137 a, 137 b in a normalmanner relative to a longitudinal axis “A” (FIG. 5) extending throughthe SULU. It is envisioned that other surgical fastener staple patterns,e.g., spiral, tangential or angular relative to axis “A”, may beutilized to achieve hemostasis between luminal structures (FIG. 25B).For example, it is contemplated that arranging the surgical fasteners260 in one of the aforedescribed patterns may enable more surgicalfasteners 260 to be employed within the same spatial considerationswhich may achieve a more consistent and/or more reliable hemostasisbetween luminal structures 320, 310.

As can be appreciated, the presently disclosed instrument and method asdescribed herein allows the user to perform an end-to-end anastomosisdeep within the colon or small intestine without the need for agastrotomy and/or other procedures necessary for the proper insertion ofthe surgical instrument. For example, the presently disclosed instrument10 may be particularly useful in low anterior resection of the colonwhereas prior devices and techniques normally require complexmanipulation and positioning of the instrument to reach the low anteriorsection of the colon and to successfully complete the anastomosis. Inmany cases, open surgical conditions were required to access thesurgical area and properly manipulate the instrument for stapling.

As can be appreciated, the a large majority of the prior art end-to-endanastomosis devices produce an eversion 500 which is interior to thelumen, e.g., colon, which may cause fibrin stenosis at the anastomosissite requiring further resection and/or other operative measure toresolve the condition (see FIG. 24B). The presently disclosed instrumentand method described herein produces an eversion 500 which is exteriorto the colon which reduces the likelihood of stenosis at the site (seeFIG. 24C). Further, a number of known end-to-end anastomotic devicesinclude a knife-like assembly which cuts away healthy tissue beyond theanastomosis to complete the anastomosis. As can be appreciated, thepresently disclosed instrument does not include a knife (or the like) tocomplete the anastomosis hence reducing the amount of healthy tissuelost during the anastomosis.

It will be understood that various modifications may be made to theembodiment shown herein. For example, the instrument may be sized toperform an anastomosis for other vessels and luminal tissue. Moreover,although the various internal components of the instrument 10 are shownengaged by particular mechanical interfaces it is envisioned that othertypes of mechanical interfaces can be employed to achieve the same orsimilar purpose, e.g., snap-fit, tongue and groove, press fit, etc.Therefore, the above description should not be construed as limiting,but merely as exemplifications of preferred embodiment. Those skilled inthe art will envision other modifications within the scope and spirit ofthe claims appended hereto.

1. A loading unit for use with a surgical instrument for performing anend-to-end anastomosis of first and second luminal structures, theloading unit comprising: a first retracting sleeve including a base anda sleeve cap, the first retracting sleeve being configured to support aplurality of fasteners on a distal end thereof; a second retractingsleeve disposed about the first retracting sleeve, the second retractingsleeve including upper and lower cuffs; and a fastener supportconfigured to house the first and second retracting sleeves, thefastener support including upper and lower supports; and wherein thesleeve cap of the first retracting sleeve, the lower cuff of the secondretracting sleeve and the lower support of the fastener support arepivotally connected with respect to the base of the first retractingsleeve, the upper cuff of the second retracting sleeve and the uppersupport of the fastener support to permit removal of a first luminalstructure therefrom after the first luminal structure is secured to asecond luminal structure.
 2. The loading unit of claim 1, furtherincluding a plurality of fasteners operably supported on a distal endthereof.
 3. The loading unit of claim 2, wherein the first and secondretracting sleeves cooperate to deform the plurality of fasteners. 4.The loading unit of claim 1, wherein each of the base and the sleeve capof the first retracting sleeve include fastener support channels eachconfigured to support the surgical fasteners.
 5. The loading unit ofclaim 1, wherein the base includes a circular lip located at a proximalend and a semi-circular anvil located at a distal end.
 6. The loadingunit of claim 5, wherein the first retracting sleeve further includes alocking tab having an elongated slit.
 7. The loading unit of claim 6,wherein the locking tab is disposed between the lip and the anvil. 8.The loading unit of claim 6, wherein the second retracting sleevefurther includes an outer cap.
 9. The loading unit of claim 1, whereinthe upper fastener is connected to the lower fastener by a hinge. 10.The loading unit of claim 1, wherein the first retracting sleeve, secondretracting sleeve and fastener support each include an aperture definedin a side thereof.
 11. The loading unit of claim 10, wherein theaperture defined in the side of each of the first retracting sleeve,second retracting sleeve and fastener support are dimensioned toincorporate the first luminal structure therethrough for loading atop aplurality of surgical fasteners.
 12. The loading unit of claim 1,further including a plurality of fasteners operably supported on adistal end thereof.
 13. The loading unit of claim 1, wherein a proximalend thereof is configured for selective engagement with an actuator. 14.The loading unit of claim 1, wherein the plurality of fasteners aresupported in an array-like fashion.